المكافحة الأحيائية لمرض موت بادرات الطماطة المتسبب عن الفطر Pythium aphanidermatum

الملخص EN

This study was conducted to evaluate the activity of Saccharomyces cerevesiae and Kluyveromyces marxianus against Pythium aphanidermatum , causative agents of tomato seedling damping – off .

P.

aphanidermatum was isolated from infected seedling .

The activity of S.

cerevesiae and K.

marxianus against P.

aphanidermatum was tested on potato dextrose agar (PDA) in petridishes .

A line of yeast growth on one side and a disk of 0.5cm from new growth of fungal culture was placed on the other side .

The effect of the yeast in controlling seedling damping off disease in pots under greenhouse condition was carried out by adding 50 ml of yeast suspention at 21 x 08 cfu/ ml of S.

cerevesiae and 3 x 106 cfu/ ml of K.

marxianus befor 6 days of cultivation and the same volum during cultivation , Tomato seeds were soaked in yeast suspention and sowing in soil contaminted with P.

aphanidermatum .

The activity of S.

cerevesiae and K.

marxianus against P.

aphanidermatum attained to 36.39 % and 32.8 % on PDA after 3 days of incubation respectively .

S.

cerevesiae at 0.1 ; 0.2 ; 0.3 ; 0.4 and 0.5 g / L .

and K.

marxianus at 9 x 105 cfu/ ml inhibited totaly fungal growth .

The yeast filtrate induced a reduction in fungal biomass weight , 41.3 and 60,1 mg for S.

cerevesiae and K.

marxianus respectively compared with 76.3 mg for control .

It was found that soil and seed treatments with K.

marxianus suspention at 31 x 06 cfu/ ml and 2 x 104 cfu/ seed were more effective than other treatment in reduction of pre and post emergence tomato seedling damping off , that were 0.0 , 0.0 compared with 50 and 16.67 % in control treatment respectively unde greenhouse condition assouated with increasing of peroxidase activity .